1. Field of the Invention
The present invention relates to pipe handling apparatus. More particularly, the present invention relates to pipe handling apparatus that have a main rotating structural member rotating about a pivot axis. More particularly, the present invention relates to controlling undesirable forces that are created while positioning a tubular at a well head. More particularly, the present invention relates to apparatus for tensioning the main rotating structural member of the pipe handling apparatus.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
Drill rigs have utilized several methods for transferring tubular members from a pipe rack adjacent to the drill floor to a mousehole in the drill floor or the well bore for connection to a previously transferred tubular or tubular string. The term “tubular” as used herein includes all forms of pipe, drill pipe, drill collars, casing, liner, bottom hole assemblies (BHA), and other types of tubulars known in the art.
Conventionally, drill rigs have utilized a combination of the rig cranes and the traveling system for transferring a tubular from the pipe rack to a vertical position above the center of the well. The obvious disadvantage with the prior art systems is that there is a significant manual involvement in attaching the pipe elevators to the tubular and moving the pipe from the drill rack to the rotary table at the well head. This manual transfer operation in the vicinity of workers is potentially dangerous and has caused numerous injuries in drilling operations. Further, the hoisting system may allow the tubular to come into contact with the catwalk or other portions of the rig as the tubular is transferred from the pipe rack to the drill floor. This can damage the tubular and may affect the integrity of the connections between successive tubulars in the well.
One method of transferring pipe from the rack to the well platform comprises tying one end of a line on the rig around a selected pipe on the pipe rack. The pipe is thereafter lifted up onto the platform and the lower end thereof is placed into the mousehole. The mousehole is simply an upright, elongate cylindrical container adjacent to the rotary table which supports the pipe temporarily. When it is necessary to add the pipe to the drill string, slips are secured about the drill string on the rotary table thereby supporting the same in the well bore. The pipe is disconnected from the traveling equipment, and the elevators, or the kelly, are connected to the pipe in the mousehole. Next, the traveling block is raised by positioning the pipe over the drill string. Tongs are used to secure the pipe to the upper end of the drill string. The drill pipe elevators suspend the drill pipe from a collar, which is formed around one end of the pipe and does not clamp the pipe, thereby permitting rotational pipe movement in order to threadably engage the same to the drill string.
A prior art technique for moving joints of casing from racks adjacent to the drilling rig comprises tying a line from the rig onto one end of a selected casing joint on the rack. The line is raised by lifting the casing joint up a ramp leading to the rig platform. As the rope lifts the casing from the rack, the lower end of the casing swings across the platform in a dangerous manner. The danger increases when a floating system is used in connection with drilling. Because the rope is tied around the casing at one end thereof, the casing does not hang vertically, but rather tilts somewhat. A man working on a platform elevated above the rig floor must hold the top of the casing and straighten it out while the casing is threaded into the casing string which is suspended in the well bore by slips positioned on the rotary table.
It is desirable to be able to grip casing or pipe positioned on a rack adjacent a drilling well, move the same into vertical orientation over the well bore, and thereafter lower the same onto the string suspended in the well bore.
In the past, various devices have been created which mechanically move a pipe from a horizontal orientation to a vertical orientation such that the vertically oriented pipe can be installed into the well bore. Typically, these devices have utilized several interconnected arms that are associated with a main rotating structural member. In order to move the pipe, a succession of individual movements of the levers, arms, and other components of the main rotating structural member must be performed in a coordinated manner in order to achieve the desired result. Typically, a wide variety of hydraulic actuators are connected to each of the components so as to carry out the prescribed movement. A complex control mechanism is connected to each of these actuators so as to achieve the desired movement. Advanced programming is required of the controller in order to properly coordinate the movements in order to achieve this desired result.
Unfortunately, with such systems, the hydraulic actuators, along with other components, can become worn with time. Furthermore, the hydraulic integrity of each of the actuators can become compromised over time. As such, small variations in each of the actuators can occur. These variations, as they occur, can make the complex mechanism rather inaccurate. The failure of one hydraulic component can exacerbate the problems associated with the alignment of the pipe in a vertical orientation. Adjustments of the programming are often necessary so to as to continue to achieve the desired results. Fundamentally, the more hydraulic actuators that are incorporated into such a system, the more likely it is to have errors, inaccuracies, and deviations in the desired delivery profile of the tubular. Typically, very experienced and knowledgeable operators are required so as to carry out this pipe movement operation. This adds significantly to the cost associated with pipe delivery.
In the past, pipe handling apparatus have not been used for the installation of casing. The problem associated with casing is that the threads of the casing are formed on an inner wall and on an outer wall at the ends of each of the casing sections. Whenever these threads are formed, the relatively thin wall thickness of the casing is further minimized. Additionally, great precision is required so as to properly thread the threads of one casing section within the threads of an adjacent casing section. The amount of accuracy required for the delivery of the casing by a pipe handling apparatus, in the past, has not been sufficient so as to achieve the desired degree of accuracy for the installation of the casing sections in their threaded connection. The improper installation of one casing section upon another casing section can potentially damage the threads associated with such casing sections. Additionally, in the past, the pipe handling apparatus could potentially damage the thin-walled casing sections during the delivery. As such, a need has developed to adapt a pipe handling apparatus so as to achieve the desired amount of accuracy for the installation of casing sections.
To address these problems and needs, U.S. application Ser. No. 11/923,451, filed on Oct. 24, 2007, by the present inventor discloses a pipe handling apparatus that has a boom pivotally movable between a first position and a second position, a riser assembly pivotally connected to the boom, an arm pivotally connected at one end to the first portion of the riser assembly and extending outwardly therefrom, a gripper affixed to an opposite end of the arm suitable for gripping a diameter of the pipe, a link pivotally connected to the riser assembly and pivotable so as to move relative to the movement of the boom between the first and second positions, and a brace having one end pivotally connected to the boom and an opposite end pivotally connected to the arm between the ends of the arm. The riser assembly has a first portion extending outwardly at an obtuse angle with respect to the second portion.
The pipe handling apparatus delivers a pipe to a well head in the second position. Pipes can be of extraordinary lengths and weights. Once the pipe is connected to other pipe in the well head, the grippers of the pipe handling apparatus release the pipe. A problem associated with the pipe handling apparatus is that once the grippers release the pipe at the well head, the apparatus springs upwardly and away from the well head. This is due to the release of the massive weight of the pipe. This springback causes unnecessary stresses on the pipe handling apparatus and can cause structural damage to the apparatus, such as cracking and bending. Upon the release of the pipe, the grippers and the arm of the pipe handling apparatus can have a springback of up to ten inches. This creates large spikes in the stresses on the boom of the pipe handling apparatus. In addition to creating unnecessary stresses on the boom, the springback can cause the pipe to be deflected at the well head. Moreover, the accuracy of the pipe handling apparatus decreases when this springback occurs. Thus, there is a need to avoid the springback and minimize the deflection of the apparatus that is caused by the release of the pipe at the well head. These problems also occur when casing is delivered to the well head by the pipe handling apparatus.
In the past, various patents and patent applications relate to apparatus and methods for stiffening a pipe handling apparatus. For example, U.S. patent application Ser. No. 12/013,979, filed on Jan. 14, 2008, by the present applicant, discloses a pre-loading system for a pipe handling apparatus in which a boom is pivotally mounted at one end to a skid and in which an arm is interconnected to an opposite end of the boom. The pre-loading system has a tensioning system with one end affixed to the arm and an opposite end fixedly mounted so as to apply tension to the arm when the arm has a load applied to an end of the arm opposite the boom. The tensioning system includes a first cable assembly having one end interconnected to the arm and an opposite end fixedly mounted, and a second cable assembly interconnected to the arm and having an opposite end fixedly mounted. The first and second cable assemblies extend from opposite sides of the arm.
U.S. Pat. No. 3,177,944, issued on Apr. 13, 1965, to R. N. Knights, describes a racking mechanism for earth boring equipment that provides for horizontal storage of pipe lengths on one side of and clear of the derrick. This is achieved by means of a transport arm which is pivoted toward the base of the derrick for swing movement in a vertical plane. The outer end of the arm works between a substantially vertical position in which it can accept a pipe length from, or deliver a pipe length to, a station in the derrick, and a substantially horizontal portion in which the arm can deliver a pipe length to, or accept a pipe length from, a station associated with storage means on one side of the derrick.
U.S. Pat. No. 3,464,507, issued on Sep. 2, 1969, to E. L. Alexander et al., teaches a portable rotary pipe handling system. This system includes a mast pivotally mounted and movable between a reclining transport position to a desired position at the site drilling operations which may be at any angle up to vertical. The mast has guides for a traveling mechanism that includes a block movable up and down the mast through operation of cables reeved from the traveling block over crown block pulleys into a drawwork. A power drill drive is carried by the traveling block. An elevator for drill pipe is carried by an arm swingably mounted relative to the power unit. Power tongs, slips, and slip bushings are supported adjacent the lower end of the mast and adapted to have a drill pipe extend therethrough from a drive bushing connected to a power drive whereby the drill pipe is extended in the direction of the hole to be drilled.
U.S. Pat. No. 3,633,771, issued on Jan. 11, 1972, to Woolslayer et al., discloses an apparatus for moving drill pipe into and out of an oil well derrick. A stand of pipe is gripped by a strongback which is pivotally mounted to one end of a boom. The boom swings the strongback over the rotary table thereby vertically aligning the pipe stand with the drill string. When both adding pipe to and removing pipe from the drill string, all vertical movement of the pipe is accomplished by the elevator suspended from the traveling block.
U.S. Pat. No. 3,860,122, issued on Jan. 14, 1975, to L. C. Cemosek, describes an apparatus for transferring a tubular member, such as a pipe, from a storage area to an oil well drilling platform. The positioning apparatus includes a pipe positioner mounted on a platform for moving the pipe to a release position whereby the pipe can be released to be lowered to a submerged position. A load means is operably attached or associated with the platform and positioning means in order to move the pipe in a stored position to a transfer position in which the pipe is transferred to the positioner. The positioner includes a tower having a pipe track pivotally mounted thereon with pipe clamp assemblies which are adapted to receive a pipe length. The pipe track is pivotally movable by a hydraulic power mechanism or gear mechanism between a transfer position in which pipe is moved into the clamp assemblies and the release position in which the pipe is released for movement to a submerged position.
U.S. Pat. No. 3,986,619, issued on Oct. 19, 1976, to Woolslayer et al., shows a pipe handling apparatus for an oil well drilling derrick. In this apparatus, the inner end of the boom is pivotally supported on a horizontal axis in front of a well. A clamping means is pivotally connected to the outer end of the boom on an axis parallel to the horizontal axis at one end. The clamping means allows the free end of the drill pipe to swing across the boom as the outer end of the boom is raised or lowered. A line is connected at one end with the traveling block that raises and lowers the elevators and at the other end to the boom so as to pass around sheaves.
U.S. Pat. No. 4,172,684, issued on Oct. 30, 1979, to C. Jenkins, shows a floor-level pipe handling apparatus which is mounted on the floor of an oil well derrick. The apparatus includes a support that is rockable on an axis perpendicular to the centerline of a well being drilled. One end of an arm is pivotally mounted on the support on an axis transverse to the centerline of the well. The opposite end of the arm carries a pair of shoes having laterally opening pipe-receiving seats facing away from the arm. The free end of the arm can be swung toward and away from the well centerline and the arm support can be rocked to swing the arm laterally.
U.S. Pat. No. 4,403,666, issued on Sep. 13, 1983, to C. A. Willis, shows self-centering tongs and a transfer arm for a drilling apparatus. The clamps of the transfer arm are resiliently mounted to the transfer arm so as to provide limited axial movement of the clamps and thereby of a clamped down hole tubular. A pair of automatic, self-centering, hydraulic tongs are provided for making up and breaking out threaded connections of tubulars.
U.S. Pat. No. 4,407,629, issued on Oct. 4, 1983, to C. A. Willis, teaches a lifting apparatus for downhole tubulars. This lifting apparatus includes two rotatably mounted clamps which are rotatable between a side loading-position so as to facilitate the loading and unloading in the horizontal position, and a central position, in which a clamped tubular is aligned with the drilling axis when the boom is in the vertical position. An automatic hydraulic sequencing circuit is provided to automatically rotate the clamps into the side-loading position whenever the boom is pivoted with a down-hole tubular positioned in the clamp. In this position, the clamped tubular is aligned with a safety plate mounted on the boom to prevent a clamped tubular from slipping from the clamps.
U.S. Pat. No. 4,492,501, issued on Jan. 8, 1985, to K. M. Haney, provides a platform positioning system for a drilling operation which includes a support structure and a transfer arm pivotally connected to the support structure to rotate about a first axis. This platform positioning system includes a platform which is pivotally connected to the support structure to rotate about a second axis, and rod which is mounted between the transfer arm and the platform. The position of the arm and platform axes and the length of the rod are selected such that the transfer arm automatically and progressively raises the platform to the raised position by means of the rod as the transfer arm moves to the raised position. The transfer arm automatically and progressively lowers the platform to the lowered position by means of the rod as the transfer arm moves to the lowered position.
U.S. Pat. No. 4,595,066, issued on Jun. 17, 1986, to Nelmark et al., provides an apparatus for handling drill pipes and used in association with blast holes. This system allows a drill pipe to be more easily connected and disconnected to a drill string in a hole being drilled at an angle. A receptacle is formed at the lower end of the carrier that has hydraulically-operated doors secured by a hydraulically-operated lock. A gate near the upper end is pneumatically operated in response to the hydraulic operation of the receptacle lock.
U.S. Pat. No. 4,822,230, issued on Apr. 18, 1989, to P. Slettedal, teaches a pipe handling apparatus which is adapted for automated drilling operations. Drill pipes are manipulated between substantially horizontal and vertical positions. The apparatus is used with a top mounted drilling device which is rotatable about a substantially horizontal axis. The apparatus utilizes a strongback provided with clamps to hold and manipulate pipes. The strongback is rotatably connected to the same axis as the drilling device. The strongback moves up or down with the drilling device. A brace unit is attached to the strongback to be rotatable about a second axis.
U.S. Pat. No. 4,834,604, issued on May 30, 1989, to Brittain et al., provides a pipe moving apparatus and method for moving casing or pipe from a horizontal position adjacent a well to a vertical position over the well bore. The machine includes a boom movable between a lowered position and a raised position by a hydraulic ram. A strongback grips the pipe and holds the same until the pipe is vertically positioned. Thereafter, a hydraulic ram on the strongback is actuated thereby lowering the pipe or casing onto the string suspended in the well bore and the additional pipe or casing joint is threaded thereto.
U.S. Pat. No. 4,708,581 issued on Nov. 24, 1987, H. L. Adair, provides a method for positioning a transfer arm for the movement of drill pipe. A drilling mast and a transfer arm are mounted at a first axis adjacent the mast to move between a lowered position near ground level and an upper position aligned with the mast. A reaction point anchor is fixed with respect to the drilling mast and spaced from the first axis. A fixed length link is pivotably mounted to the transfer arm at a second axis, spaced from the first axis, and a first single stage cylinder is pivotably mounted at one end to the distal end of the link and at the other end to the transfer arm. A second single stage hydraulic cylinder is pivotably mounted at one end to the distal end of the link and at the other end to the reaction point.
U.S. Pat. No. 4,759,414, issued on Jul. 26, 1988, to C. A. Willis, provides a drilling machine which includes a drilling superstructure skid which defines two spaced-apart parallel skid runners and a platform. The platform supports a drawworks mounted on a drawworks skid and a pipe boom is mounted on a pipe boom skid sized to fit between the skid runners of the drilling substructure skid. The drilling substructure skid supports four legs which, in turn, support a drilling platform on which is mounted a lower mast section. The pipe boom skid mounts a pipe boom as well as a boom linkage, a motor, and a hydraulic pump adapted to power the pipe boom linkage. Mechanical position locks hold the upper skid in relative position over the lower skid.
U.S. Pat. No. 5,458,454, issued on Oct. 17, 1995, to R. S. Sorokan, describes a pipe handling method which is used to move tubulars used from a horizontal position on a pipe rack adjacent the well bore to a vertical position over the wall center. This method utilizes bicep and forearm assemblies and a gripper head for attachment to the tubular. The path of the tubular being moved is close to the conventional path of the tubular utilizing known cable transfer techniques so as to allow access to the drill floor through the V-door of the drill rig. U.S. Pat. No. 6,220,807 describes apparatus for carrying out the method of U.S. Pat. No. 5,458,454.
U.S. Pat. No. 6,609,573, issued on Aug. 26, 2003, to H. W. F. Day, teaches a pipe handling system for an offshore structure. The pipe handling system transfers the pipes from a horizontal pipe rack adjacent to the drill floor to a vertical orientation in a set-back area of the drill floor where the drill string is made up for lowering downhole. The cantilevered drill floor is utilized with the pipe handling system so as to save platform space.
U.S. Pat. No. 6,705,414, issued on Mar. 16, 2004, to Simpson et al., describes a tubular transfer system for moving pipe between a substantial horizontal position on the catwalk and a substantially vertical position at the rig floor entry. Bundles of individual tubulars are moved to a process area where a stand make-up/break-out machine makes up the tubular stands. The bucking machine aligns and stabs the connections and makes up the connection to the correct torque. The tubular stand is then transferred from the machine to a stand storage area. A trolley is moved into position over the pick-up area to retrieve the stands. The stands are clamped to the trolley and the trolley is moved from a substantially horizontal position to a substantially vertical position at the rig floor entry. A vertical pipe-racking machine transfers the stands to the traveling equipment. The traveling equipment makes up the stand connection and the stand is run into the hole.
U.S. Pat. No. 6,779,614, issued on Aug. 24, 2004, to M. S. Oser, shows another system and method for transferring pipe. A pipe shuttle is used for moving a pipe joint into a first position and then lifting upwardly toward an upper second position.
It is an object of the present invention to provide an apparatus and method for enhancing the structural integrity of a main rotating structural member of a pipe handling apparatus when delivering a pipe to a well head.
It is another object of the present invention to provide an apparatus and method for stiffening a main rotating structural member of a pipe handling apparatus that minimizes the amount of calibration required in order to move the pipe from a horizontal orientation to a vertical orientation.
It is another object of the present invention to provide an apparatus and method for stiffening a main rotating structural member of a pipe handling apparatus that operates within a single degree of freedom so as to move the pipe without adjustments between the components.
It is still another object of the present invention to provide an apparatus and method for stiffening the main rotating structural member of a pipe handling apparatus that minimizes the number of components added to the apparatus so as to accomplish such stiffening.
It is another object of the present invention to provide an apparatus and method for stiffening a pipe handling apparatus that prevents damage of the components of the pipe handling apparatus.
It is another object of the present invention to provide an apparatus and method for stiffening a pipe handling apparatus that prevents sideways or transverse motions of the pipe handling apparatus.
It is another object of the present invention to provide an apparatus and method for stiffening that achieves greater precision in the delivery and insulation of pipe and/or casing.
It is another object of the present invention to provide an apparatus and method for stiffening a pipe handling apparatus that increases the structural stiffness of the apparatus.
It is another object of the present invention to provide an apparatus and method for stiffening pipe that serves to minimize the weight and size of the components of the main rotating structural member of a pipe handling apparatus.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.